English verb conjugation
COULD DUN

Regular verb: dun - dunned - dunned

Affirmation

Simple form	V-ing form
I could dun you could dun he could dun we could dun you could dun they could dun	I could be dunning you could be dunning he could be dunning we could be dunning you could be dunning they could be dunning
Perfect	V-ing perfect
I could have dunned you could have dunned he could have dunned we could have dunned you could have dunned they could have dunned	I could have been dunning you could have been dunning he could have been dunning we could have been dunning you could have been dunning they could have been dunning

Negation

Simple form	V-ing form
I couldn't dun you couldn't dun he couldn't dun we couldn't dun you couldn't dun they couldn't dun	I couldn't be dunning you couldn't be dunning he couldn't be dunning we couldn't be dunning you couldn't be dunning they couldn't be dunning
Perfect	V-ing perfect
I couldn't have dunned you couldn't have dunned he couldn't have dunned we couldn't have dunned you couldn't have dunned they couldn't have dunned	I couldn't have been dunning you couldn't have been dunning he couldn't have been dunning we couldn't have been dunning you couldn't have been dunning they couldn't have been dunning

Interrogative form

Simple form	V-ing form
could I dun? could you dun? could he dun? could we dun? could you dun? could they dun?	could I be dunning? could you be dunning? could he be dunning? could we be dunning? could you be dunning? could they be dunning?
Perfect	V-ing perfect
could I have dunned? could you have dunned? could he have dunned? could we have dunned? could you have dunned? could they have dunned?	could I have been dunning? could you have been dunning? could he have been dunning? could we have been dunning? could you have been dunning? could they have been dunning?

Interro-negative form

Simple form	V-ing form
couldn't I dun? couldn't you dun? couldn't he dun? couldn't we dun? couldn't you dun? couldn't they dun?	couldn't I be dunning? couldn't you be dunning? couldn't he be dunning? couldn't we be dunning? couldn't you be dunning? couldn't they be dunning?
Perfect	V-ing perfect
couldn't I have dunned? couldn't you have dunned? couldn't he have dunned? couldn't we have dunned? couldn't you have dunned? couldn't they have dunned?	couldn't I have been dunning? couldn't you have been dunning? couldn't he have been dunning? couldn't we have been dunning? couldn't you have been dunning? couldn't they have been dunning?